Perform these steps at ypur won risk. Plz take the backup of your regisrty before doing so....!
1. Delete the following files if present
%windir%\pif\cvt.exe
%windir%\INF\inf31.exe
inf31.exe
IDTemplate.exe
%windir%\Application Data\IDTemplate.exe
%profiledir%\Local Settings\Application Data\GavGent.B
IDTemplate.exe
%mypicturesdir%\about.Brontok.A.html
2. Delete any Cookies by Brontok.A
3. Delete the following registry key
Brontok.A does not create any registry keys
And registry valyues
SystemGent
IDTemplates
Reboot your system and reboot if the problem prevails or not.
Source >>
http://www.scanspyware.net/info/Brontok.A.htm